In many applications of biological imaging and machine vision it is desirable to obtain three dimensional, volumetric images of a sample. Photographic and topologic representations of surface structure and features provide important, but limited, information about a sample. It is often desirable to visualize the interior of samples for diagnostic purposes.
There are many techniques for obtaining tomographic and volumetric images of samples. Generally a radiation source, imaging methodology, and image reconstruction methodology are chosen to match the transmissive properties and scale of the sample. For example, conventional techniques may include Magnetic resonance imaging (MRI), computed tomography (CT) scans and positron emission tomography (PET) scans.
In the optical domain, optical coherence tomography (OCT) has obtained significant traction for its ability to acquire depth resolved images with longitudinal and lateral resolutions relevant to investigation of biological tissues, and has been adopted as a standard of care in clinical retina diagnostics.
OCT has the capability to resolve structures at resolutions of better than 10 μm, with the potential to serve as a non-invasive substitute to sectioning histology. In order to be a successful substitute to histology, OCT image acquisition and processing methods must take advantage of thick-section imaging to create visualizations that highlight tissue physiopathology in longitudinal and lateral dimensions at cellular or near-cellular resolution, on living subjects.